1. Field of the Invention
This specification relates to an electric motor and an electric vehicle having the same, and particularly, to an electric motor capable of enhancing a cooling performance by increasing a heat exchange area between components, and an electric vehicle having the same.
2. Background of the Invention
Generally, a motor or an electric motor (hereinafter, will be called ‘electric motor’) is an apparatus for converting electric energy into mechanical energy.
This electric motor may be categorized into a direct current (DC) motor and an alternating current (AC) motor according to used power.
The AC motor includes a three-phase AC motor and a single-phase AC motor, and each AC motor has an induction motor and a synchronous motor.
The induction motor has many advantages, such as direct connection to power, a simplified and rigid structure and low prices, and can be easily dealt. Accordingly, the induction motor is being widely used.
Recently, the electric motor is being adopted as a driving source of vehicles including automobiles, so as to reduce environmental pollutions due to harmful gases occurring when fuels of the vehicles are combusted, and so as to reduce the amount of resources (fuels).
The electric motor used as a driving source of an electric vehicle may comprise a frame having an accommodation space therein, a stator disposed in the frame, and a rotor disposed to be rotatable with respect to the stator.
The electric motor for an electric vehicle may generate heat of high temperature due to its large capacity. More concretely, when the electric motor is driven, heat of high temperature may be generated from the stator due to copper loss and/or iron loss or core loss.
For cooling, the electric motor for an electric vehicle may be provided with cooling means.
The cooling means may be configured to cool the frame, for instance.
As the cooling means, may be used an air-type cooling means for cooling the frame by blowing air with using a fan, and a water-type cooling means for cooling the frame by using a liquid such as water.
However, the conventional electric motor may have the following problems.
Firstly, since a contact area between the stator and the frame is not wide, heat generated from the stator may not be rapidly transmitted to the frame. This may cause the stator and the rotor to have increased temperatures. If the temperatures of the stator and the rotor are excessively high, copper loss and iron loss may be increased. This may lower an output and efficiency.
Furthermore, since the stator and the frame are respectively formed in a circular shape, the stator may perform a relative rotation in a circumferential direction with respect to the frame when the electric motor is driven. This may shorten the lifespan of the electric motor.